[英]Node.js hangs on multiple setTimeout looping calls
我正在嘗試編寫允許我暫停播放音頻文件的類。 該類接受原始的PCM數據,並且您向該類提供發送樣本塊的頻率。 例如,您可以指定每20毫秒傳遞一個塊。 該類還實現了pause()和resume()函數。
該類還使用我編寫的SerialQueue模塊,以確保不會同時在緩沖區上對數據進行切片和連接。 因此,在下面的代碼中您將看到很多對此的引用。
我遇到的問題是它將多次調用setTimeout,但最終在setTimeout上隨機凍結。 我的處理器使用率將立即上升,並且沒有任何其他反應。
這是完整的代碼以及我的測試代碼:
var nopus = require( './lib/node-opus' );
var Speaker = require( 'speaker' );
var fs = require( 'fs' );
var path = require( 'path' );
var SerialQueue = require( './lib/serial-queue' );
var Transform = require( 'stream' ).Transform;
var inherits = require( 'util' ).inherits;
function ThrottlePCM( opts ) {
// Default to an empty object
if( !opts )
opts = {};
// Pass through the options
Transform.call( this, opts );
this.milliseconds = opts.milliseconds | 20;
this.bitDepth = opts.bitDepth | 16;
this.channels = opts.channels | 1;
this.sampleRate = opts.sampleRate | 48000;
// Set our frame size
if( this.milliseconds==2.5 )
this.frameSize = this.sampleRate/400;
else if( this.milliseconds==5 )
this.frameSize = this.sampleRate/200;
else if( this.milliseconds==10 )
this.frameSize = this.sampleRate/100;
else if( this.milliseconds==20 )
this.frameSize = this.sampleRate/50;
else if( this.milliseconds==40 )
this.frameSize = this.sampleRate/25;
else if( this.milliseconds==60 )
this.frameSize = 3*this.sampleRate/50;
else
throw new Error( "Millisecond value is not supported." );
this.bytesPerBeat = this.frameSize*this.bitDepth/8*this.channels;
console.log( "Bytes per beat %d.", this.bytesPerBeat );
this.buffer = null;
this.queue = new SerialQueue();
// Taken from TooTallNate
this.totalBytes = 0;
this.startTime = Date.now();
this.pauseTime = null;
// Can we pass
this.canPass = true;
this.paused = false;
this.flushCallback = null;
}
inherits( ThrottlePCM, Transform );
ThrottlePCM.prototype._transform = function( data, encoding, done ) {
var that = this;
this.queue.queue( function() {
// Append the buffer
if( that.buffer )
that.buffer = Buffer.concat( [ that.buffer, data ] );
else
that.buffer = data;
// Nen no tame
if( that.canPass )
that.passThrough();
} );
// We are ready for more data
done();
};
ThrottlePCM.prototype.pause = function() {
this.paused = true;
this.pauseTime = Date.now();
};
ThrottlePCM.prototype.resume = function() {
this.paused = false;
this.startTime+= Date.now()-this.pauseTime;
console.log( "Difference is %d: %d", Date.now()-this.pauseTime, this.startTime );
var that = this;
this.queue.queue( function() {
that.passThrough();
} );
};
ThrottlePCM.prototype.passThrough = function() {
// Are we paused?
if( this.paused ) {
this.canPass = true;
return;
}
// No pass now
this.canPass = false;
// The rest of us
var that = this;
var totalBeats = (Date.now()-this.startTime)/this.milliseconds;
var expected = totalBeats*this.bytesPerBeat;
function passMe() {
console.log( "== Inkasemeen" );
that.queue.queue( function() {
if( !that.buffer ) {
// Should we just flush?
if( that.flushCallback ) {
var callback = that.flushCallback;
that.flushCallback = null;
console.log( "Antipass" );
callback();
}
else
that.canPass = true; // We can pass now from on timer
return;
}
var output;
if( that.buffer.length>that.bytesPerBeat ) {
output = that.buffer.slice( 0, that.bytesPerBeat );
that.buffer = that.buffer.slice( that.bytesPerBeat );
}
else {
output = that.buffer;
that.buffer = null;
}
that.push( output );
that.totalBytes+= output.length;
// Re-call us
that.passThrough();
} );
}
console.log( "--\nTotal Beats: %d\nTotal Bytes: %d\nExpected: %d\nBytes Per Beat: %d\nMilliseconds: %s", totalBeats, this.totalBytes, expected, this.bytesPerBeat, this.milliseconds );
if( this.totalBytes>expected ) {
var remainder = this.totalBytes-expected;
var sleepTime = remainder/this.bytesPerBeat*this.milliseconds;
console.log( "++\nSleep time: %d", sleepTime );
if( sleepTime ) {
setTimeout( passMe, sleepTime );
}
else {
passMe();
}
}
else {
console.log( "Bytes are higher by %d (%d-%d)", expected-this.totalBytes, expected, this.totalBytes );
passMe();
}
};
ThrottlePCM.prototype._flush = function( done ) {
console.log( "Flush called." );
// No action here I don't think
this.flushCallback = done;
var that = this;
this.queue.queue( function() {
// Show ourselves flushy
if( that.canPass )
that.passThrough();
} );
};
var format = {
channels: 1,
bitDepth: 16,
sampleRate: 48000,
bitrate: 16000,
milliseconds: 60
};
var rate = nopus.getFrameSizeFromMilliseconds*format.channels*nopus.binding.sizeof_opus_int16;
var speaker = new Speaker( format );
var decoder = new nopus.Decoder( format );
var throttle = decoder.pipe( new ThrottlePCM( format ) );
throttle.pipe( speaker );
var file = fs.createReadStream( path.join( __dirname, 'files/audio/233' ) );
file.pipe( decoder );
這將產生以下輸出:
Bytes per beat 5760.
--
Total Beats: 0.1
Total Bytes: 0
Expected: 576
Bytes Per Beat: 5760
Milliseconds: 60
Bytes are higher by 576 (576-0)
== Inkasemeen
--
Total Beats: 0.15
Total Bytes: 1920
Expected: 864
Bytes Per Beat: 5760
Milliseconds: 60
++
Sleep time: 11
== Inkasemeen
--
Total Beats: 0.26666666666666666
Total Bytes: 7680
Expected: 1536
Bytes Per Beat: 5760
Milliseconds: 60
++
Sleep time: 64
== Inkasemeen
--
Total Beats: 1.3666666666666667
Total Bytes: 13440
Expected: 7872
Bytes Per Beat: 5760
Milliseconds: 60
++
Sleep time: 58
== Inkasemeen
--
Total Beats: 2.3833333333333333
Total Bytes: 19200
Expected: 13728
Bytes Per Beat: 5760
Milliseconds: 60
++
Sleep time: 57
== Inkasemeen
--
Total Beats: 3.283333333333333
Total Bytes: 24960
Expected: 18912
Bytes Per Beat: 5760
Milliseconds: 60
++
Sleep time: 63
== Inkasemeen
--
Total Beats: 4.35
Total Bytes: 30720
Expected: 25055.999999999996
Bytes Per Beat: 5760
Milliseconds: 60
++
Sleep time: 59.000000000000036
它始終掛在不同的位置。 如您所見,它會在調用passMe函數並打印“ == Inkasemeen”之前停止在右側。
我的Node.js版本是v0.10.30。
一如既往,非常感謝!
找到了問題! 事實證明,Node.js不喜歡您將小數傳遞給setTimeout! 四舍五入解決了該問題。
if( sleepTime>0 ) {
setTimeout( passMe, sleepTime|0 );
}
else {
passMe();
}
讓我知道這段代碼是否對任何人有用。 如果是這樣,我可以在完成后發布一個github。 現在,它可以完全正常工作。
還請注意,TooTallNate已經提供了一個Throttle模塊,該模塊可能滿足大多數人對流進行節流的需求https://github.com/TooTallNate/node-throttle 。
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